Smaller campervans can use a portable potty toilet, instead of a cassette type toilet. These work reasonably well but they do of course need emptying, Example of chemical toilet: Kampa Khazi...

A swivel cassette toilet will usually have a 180 degree bowl rotation, This allows you to move into a comfortable position when using, but you can fit the toilet unit in an unusual...

Portable toilets are made up of a plastic toilet bowl and seat, and small waste tank. The two can be separated like the cassette toilet. When full, you remove the lower tank from the upper...

The unit provides a compact toilet bowl that’s sits over a small, removable waste tank cassette. The cassette  is removed through a hatch at the outside, and emptied into a waste...

An electric powered blades system chop up the waste into slurry before pumping it into a holding tank. Again, this technology allows the toilet and waste tank to be positioned apart from each...